With concern for the environment growing, the market for Bharat Heavy Electricals Ltd's (BHEL) eco-friendly battery powered "electravan" appears to be increasing.BHEL recently secured an order for manufacture and supply of four Battery Powered Road Vehicles (BPRV) to Anna Zoological Park, Chennai.The zero-emission BPRV, called 'electravan', which runs on batteries charged by electricity, will help to protect the ecosystem of the zoological park from environmental degradation caused from diesel and petrol vehicles.