The Big Lemon Solar Bus project
Brighton’s transportation company The Big Lemon has joined forces with Brighton Energy Cooperative (BEC) and announced plans to make their
green buses even greener. For the last eight years, the company’s fleet of buses was running on waste cooking oil from local restaurants, which was processed into biodiesel. Since 2007 over half a million tonnes of waste cooking oil has been used, saving over 900 tonnes of CO2 from going into the atmosphere.
As biodiesel buses are not suitable for conversion though, the company aims to buy 3 used diesel buses and convert them to electric ones, which will have zero-emissions and a very small carbon footprint. The buses will be powered by clean renewable energy produced by the solar panels that will be installed on the roof of the bus depot. In order to realize this project, The Big Lemon already raised £250,000 of investment in a bond issue, exceeding the original target of £100,000. The company has also been shortlisted for the M&S Energy Community Fund, which could bring up an additional £25,000 (the cost of the solar panel installation at the depot) through a public vote and pledged donations from voters. The depot’s roof will be covered with 120 solar panels, generating 30kWh of electricity, enough to power the whole of the 52 route between Woodingdean and Brighton city center. The Big Lemon wants to power all five of its routes this way eventually while its coach fleet, used for longer distances, will continue to use waste cooking oil. “Electric bus technology has progressed quite far. We wanted to try that and embrace it,” says Tom Druitt, managing director of The Big Lemon. The key thing about The Big Lemon idea is that the energy will be generated on site. “If we run on mains electricity then we still have a large carbon footprint,” he added.
The company has decided to convert diesel buses to run on electricity, instead of buying brand new electric ones, as a more cost effective solution. The initial purchase cost was around £20,000 for each bus and the conversion cost another £140,000, whereas a new electric bus would cost between £250,000 and £500,000 depending on the brand. Around £20,000 a year will also be saved in fuel costs, and maintenance costs will be less. “We’ve estimated that there’s a six-year payback on these buses and we’re calculating for an eight-year life span, so essentially we get two years free,” Druitt explains.
“By not putting it into the grid it makes it a bit more difficult as you come across this commonly found issue with renewables, that they’re intermittent,” says Will Cottrell, chairman of BEC. “You need to think quite hard about how it works technically,” he adds, explaining that getting the right size battery and overall system is key to providing the right level of supply. “But this is the way it’s got to be,” he says. “To move us away from a centralized energy system we need to move away from a centralized grid as well, so we need to understand the technology that is going to enable us to do that.”
Will Cottrell of the Brighton Energy Cooperative (left) and Tom Druitt, managing director of The Big Lemon. Photograph: The Big Lemon
Using an innovative combination of three renewable technologies, the project will generate clean energy during the day, store it in a battery and then charge up the Solar Buses overnight. Credits: The Big Lemon
Source: The guardian