Breaking the energy mould
Breaking the energy mouldFriday 19th February 2016
Cafe Mor, our flagship beach shack which serves local food daily at Freshwater West Beach between Easter and the end of September has become the second of only two mobile food outlets to run on solar and wind energy in the whole of the UK. Ourselves and another Pembrokeshire business based on the Honeyborough roundabout in Neyland are the first in the UK (according to NCASS the national caterers association) to try alternative energy supplies for cooking and refrigeration on board a non permanent food outlet.
Our energy project was funded by Pembrokeshire National Park. Read our official case study below.
• The last few years have seen massive leaps forward in the quality and range of street food available in the UK. Products and branding have moved into the 21st century - but the services fuelling them have not. Most vans and trailers are still powered by noisy generators, carbon intensive electricity hook-ups or expensive LPG gas.
• Pembrokeshire Beachfood won Sustainable Development Fund support from Pembrokeshire Coast National Park Authority in March 2015 to test out an approach that could revolutionise the industry and significantly reduce greenhouse gas emissions.
• Pembrokeshire Beachfood’s Cafe Môr concession operates from a remote site in West Wales with no grid connection. To date, electrical power has been provided by a generator during the day, and a hook up at a local farm by night.
• Sustainable Development Fund support was used to part fund the installation of solar PV panels and a small turbine, along with a solar inverter and a battery bank. The system has removed the need for a noisy, carbon fuelled petrol generator by day, and should reduce electrical demand at night (with mains electricity used to top up the batteries if required, rather than being the sole source of power during the night).
• Instant benefits to the business include a reduction in generator noise, less staff time required for generator operation and maintenance, fewer days lost trading due to generator issues and increased power security as a result of having a battery back-up.
• Initial calculations suggest that the system, which cost around £7500 ex. VAT, could pay for itself within three years, by means of savings in petrol for the generator, staff time operating and maintaining it, and a reduction in days lost trading from generator issues.
• Systems which eliminate the need to pay for expensive electric hook ups at festivals and events could pay back even quicker.
• The height and weight of renewable systems need to be carefully considered for safe transport of the mobile unit, and the design of the system needs to minimise shading and/or turbulence. Designing in renewables whenever a new unit is being considered will give the maximum potential for self-sufficiency and significant reductions in running cost and greenhouse gas emissions.
• The next stage of the project will monitor the electricity generated by the system over the summer. Another case study will be available in October 2015.
• Future phases of the project will look at options for reducing the impact of LPG and vehicle fuel.
There are approximately 10,000 mobile caterers in the UK who trade at wide variety of locations, from roadsides to festivals, to the burgeoning street food markets. Mobile catering has become hugely fashionable in the last 5 years; dubbed “street food” by the media, the UK has seen a surge in the new generation of mobile catering which celebrates local food cooked to restaurant standards. This new generation of street food has seen traceability, local, sustainable, high quality and sense of place put back on the menu. Café Môr has been part of this new generation and has been very successful in winning national accolades for its food as well as sustainability awards for its use of local shellfish and fish.
However, while the food, branding, concepts and designs associated with new generation street food have stepped into the 21st century, the systems powering these trailers/ food trucks are very much based on 20th century technology. If food businesses are willing to spend anywhere up to £50,000 for a new catering trailer / van, then renewable technology and sustainable, energy efficient systems should be part of any new build as standard.
The potential benefits of renewable technology for street food business include -
1. Reducing impact on the environment, and being able to use this in branding and publicity
2. Providing a more pleasant environment for customers to eat their food (i.e. without the noise and fumes of a generator or vehicle engine running nearby)
3. Saving money on electricity, LPG and/or generator fuel
4. More reliable source of power - you are self-sufficient and don't need to worry about generators breaking down, plugging into expensive power systems at festivals etc. etc.
5. Reduction in staff time needed for setting up, maintaining and filling up a generator
Pembrokeshire Beachfood has traded at Freshwater West since 2013. The Cafe Môr trailer offers a range of high quality food inspired by its surroundings - from burgers served in rolls with laver seaweed infused butter, to crab rolls and wraps made with wild garlic pesto. Of course there are also the obligatory ice-creams to cool down or hot teas and coffees to warm up that every beach trailer must provide!
The concession at Freshwater West runs from Easter to the end of September every year. The beach is wild and beautiful - perched at the very southwest tip of Pembrokeshire it has always been popular with surfers and locals, but recent years have seen the location surge in popularity, partly due to the filming of a number of high profile films at the beach. The site is managed by the National Park and the National Trust.
Until the start of this project in March 2015, electrical power for fridges, freezers and other appliances was provided to the trailer by means of a generator during the day, and via an electrical hook-up at an overnight storage location at a nearby farm.
Company founder Jonathan Williams commented ‘The location for Cafe Môr was a dream come true. However, ever since I started trading there in 2013 I have felt guilty rocking up in the morning and starting the generator up. In such a setting the noise of even the supposedly new generation ‘silent’ generators is completely at odds with the natural surroundings. That’s why I was so excited to get Sustainable Development Fund support from the National Park to explore other options’.
First steps – energy efficiency
The first step for any energy project is a review of current consumption. The initial ‘electrical load’ of Cafe Mor was around 3.4kW - this was reduced to just 370W by replacing equipment with more energy efficient equipment or using alternative methods which don't use power to achieve the same outcomes.
• Wind turbine (Rutland Wind Charger 914i, 24V) mounted onto scaffold poles on the reinforced towing end of the trailer. Turbine diameter 900mm, hub height 1m above trailer, around 3m from the ground. Maximum power 262W @ 15m/s. This type of turbine is usually used on boats.
• 4x 250W solar PV panels, mounted 2x2 onto a south facing frame on the top of the trailer. Total panel size around 3.4m x 2m (on an angle, so roof space doesn’t need to be as large as the panel area).
• Solar inverter - to convert power from the PV panels into power suitable for charging the batteries
• 4x solar batteries - to provide 11.4kWh of storage
Item Cost (ex VAT)
A++ rated fridge/freezer £450
A+ rated small chest freezer Around £100 (already in stock)
4x 250W solar panels £623
Solar inverter £1215
Wind turbine £567
4x batteries (11.4kWh storage) £1729
Monitor to be fitted £500
Installation costs £2500
TOTAL (ex VAT) £7684
• Beautiful, beautiful peace and quiet! A huge benefit for Cafe Môr staff and customers, and for the surf school who base their trailer next door.
• Reduced staff time associated with daily generator chores - estimated at an hour a day to purchase fuel, set up and take down. Over 185 days trading this is worth over £1200 in staff time per season alone.
• Reduction in non-trading days associated with generator issues - at least 2 or 3 days per year
• Increased power security - if there is a problem with power supply then the batteries will kick in, therefore reducing the risk of losing stock if problems occur when the unit is unoccupied (e.g. overnight)
• Reduced health and safety and wellbeing risks associated with generator lifting, fumes and noise.
• Reduced air, noise, land and water pollution risks associated with generator use
Cafe Môr at Freshwater West used around 1000 litres of petrol to fuel the generator in 2014. This would have cost around £1300 inc. VAT based on average petrol prices in 2014. Assuming the system can be optimised to minimise mains battery charging to almost zero, benefits in terms of reduced petrol consumption, reduced staff time and reduced loss of trading could be in the region of £2500 per year. This would give an excellent payback time for the system of around 3 years. However, the next phase of this project is a period of monitoring to establish exactly how much the system generates and therefore how much mains charging is required.
Payback times for systems mounted on vans or trailers regularly used at events could be even better, although a bedding in period to test the ability of the system to run completely off-grid would be required to ensure the van or trailer could run self-sufficiently for the duration of the event. Initial indications are that the system installed on the Cafe Môr trailer at Freshwater West has the potential to power a similar outlet for the duration of an event - with three days battery life plus wind or solar recharge during the the course of a week or 10 day long event. Assuming an electricity hook-up cost of £450+VAT per event, over 10 events over the course of a year this would give a payback of less than 2 years on a system costing up to £9000 excluding VAT (the Cafe Mor system cost just £7500 ex. VAT).
Of course this is not just about money - there is significant potential here for the industry as a whole to reduce their impact on the environment, and particularly greenhouse gas emissions. 1000 litres of petrol is equivalent to 2.33 tonnes of greenhouse gas emissions per year. Scaled up across the industry of 10,000 units this is a potential saving of 20,000 tonnes CO2e/yr. To put this in context the greenhouse gas emissions associated with a house can range from 5 - 15 tonnes per year.
ISSUES ENCOUNTERED AND RECOMMENDATIONS SO FAR
Finding an installer
Renewable systems for catering trailers are not familiar to most installers - they can make money more reliably by sticking to ‘safe’ jobs like domestic or small commercial systems. Pembrokeshire Beachfood, through their unique position in the industry and previous sustainability awards, were able to secure advice from an expert that works on the renewable systems at Glastonbury. A local installer was eventually found who had recently installed a small system on his wife’s catering trailer. We recommend that the Nationwide Caterers Association (NCASS) consider setting up an approved installer list should this project prove successful.
The maximum power that this system can regularly provide at any given time is 750W. Although the solar PV panels are rated at 1kW and the wind turbine at 140W (1.14kW) in total – this is a maximum potential output and they will usually run at far less than this, and output will be very variable across the course of a day and over the season or the year. Therefore batteries are provided to provide an even, reliable, year round supply, and these can be topped up from the mains if required. Even though the batteries could in theory deliver 11kWh, which equates to 1.4kW for 8 hours, to preserve the batteries it is recommended that they are not discharged below 50%.
A 750W limit is relatively low compared to most outlets which are set up to 16 amp (3kW) or up to 32 amp (8kW) for large outlets. This means that a renewables powered system needs to be based on very efficient kit. Efficient kit of course has benefits in itself in that it significantly reduces running costs (for example a new efficient fridge freezer can cost 75% less than an old inefficient one to run).
Every trailer or van has a maximum safe towing or driving weight. Many mobile caterers are likely to be working very close to this with the existing kit in their trailer or van, particularly when the vehicle or trailer is loaded up for a busy day’s trading or with supplies for a long event. The extra, potentially significant weight of a turbine and/or solar PV panels needs to be carefully calculated, and the existing load adjusted to take this into account. The batteries for this system on their own weighed 50kg each, 200kg in total, a significant proportion of the ‘plated weight’ for the trailer of 1680kg.
Of course additional weight also increases transport costs - so this needs to be factored into the payback calculations for units that often travel long distances.
All mobile caterers know that space is precious, the installation of the system does take up space but it is only restricted to the placement of the batteries. In this case two batteries were placed on top of each of the wheel arches, which was only “dead space” and access to the inverter means a loss in total of approximately 1m2. Batteries could be added externally to eliminate loss of space.
Wind turbine efficiency increases significantly with increased wind speed, which in turn increases with height. The relationship between wind speed and potential turbine output is non-linear - i.e. a relatively small increase in height and therefore wind speed can have a big impact on output. However, in order to get a mobile catering unit to its location there will usually be a range of bridges, trees and other obstructions that will limit the potential height of a turbine. The turbine on the Cafe Môr trailer was initially designed so that the scaffold poles could be taken down each evening and re-fixed each morning in order to maximise operating hub height. This turned out to be a difficult and cumbersome task for the member of staff operating the unit and the decision was taken to leave the turbine at a fixed height to avoid potential damage to the turbine or injury to staff.
An additional consideration when considering turbine height is that higher wind speeds associated with greater height will require additional reinforcement and specifications for the mounting - again with associated impacts on weight.
A telescopic mount was considered, but this proved too heavy and expensive.
The Cafe Môr trailer was not initially designed with a renewable system in mind - as a result the reinforced, towing end of the trailer does not face the prevailing wind. This means that the turbine is often subject to significant turbulence from the trailer and the PV panels, which affects the performance of the turbine as it is often ‘searching’ for the wind direction, as the wind swirls around the trailer and the PV panels. This could be avoided if a renewable system was designed into a new unit for a permanent or semi-permanent home, however this would always be a potential issue for a truly mobile unit as every site would be different.
Shading of the PV panels is not an issue at Freshwater West, however this could be a problem in more urban locations, and an unknown factor at festivals or events.
Energy hungry coffee machines!
Many street food providers live by their ‘proper’ coffee machines. However at Freshwater West ‘posh coffee’ simply wasn’t feasible as part of the Cafe Môr offering - even with the huge reductions made in electricity consumption of other kit the 3.2kW generator struggled to power the coffee machine. Cafe Môr now offers filter coffee in a cafeteria with hot water from the LPG water boiler instead.
RECOMMENDATIONS SO FAR
1. If you are planning a new mobile catering unit consider renewables from the outset. Designing these systems in from the outset will reduce costs and generating potential, therefore making it highly likely that you could have a self-sufficient system that significantly reduces your running costs.
2. A sizeable battery system is highly recommended - this will help to reduce some of the uncertainty around potential generation at unfamiliar sites or associated with unfavourable weather conditions.
3. You will probably need the safety net of an overnight or back-up plug in to charge your batteries, or an emergency generator, for at least the first year of operation.
by The Captain