Fossil fuels - oil, coal and gas - powered the economic growth of the past century. But along with improved living standards and increased life expectancy came new fears about potentially devastating climate change. One decade into the 21st century, there is little sign that these old-fashioned hydrocarbons are loosing ground to the new green technologies designed to mitigate carbon-related climate change. If anything, in the wake of the radiation release at the Fukushima power plant in Japan, fossil fuels are consolidating their position as the energy supply if not of choice, then of necessity. as countries around the world rethink their commitment to nuclear power, which in recent years has been rehabilitated as the answer to the world's quest for a low-carbon future, it is increased flows of oil, gas and coal that look set to step into the supply breach - at least in the short term.  Indeed, a recent report from the International Energy agency, the energy watchdog of the Organisation for Economic Co-operation and Development (OECD), points out that surging demand for fossil fuels is outstripping deployment of clean energy technologies. Coal met 47 per cent of the global new electricity demand over the past decade, eclipsing clean energy efforts made over the same period of time. This continued appetite for fossil fuels puts at risk the UN Cancun climate agreement to limit the growth in global average temperatures to less than 2C.  Renewable energy is attracting more investment as countries struggle to meet climate pledges for 2020 and beyond. Solar and wind power lead the pack. according to the IEa, at least 10 countries have sizeable domestic solar energy markets, up from just three in 2000, while installed wind power capacity has increased more than 10 fold, from 17 gigawatts (GW) at the end of 2000 to 194GW at the end of 2010. In the UK, wind power delivered more than 10 terawatt hours (TWh) of electricity in 2010, up 7.7 per cent on 2009, enough to supply more than two million homes. at least 3GW of new wind power is expected be added to the current installed capacity of 5.2GW by the end of 2012, increasing the annual contribution to around 22TWh.  There are many, however, who are openly hostile to wind power, seeing the turbines as a blight on the landscape and the technology as a waste of taxpayer-funded subsidy. This is because installed capacity doesn't truly reflect the contribution of wind power, which is, of course, dependent on the wind blowing. according to the wind and marine energy lobby group RenewableUK, wind turbines generate electricity for 70-85 per cent of the time, but not always at full output. While load factors vary according to the site and the type of turbine, the typical figure for wind is around 30 per cent. Issues of variability and intermittency mean the national power system is reliant on back-up base-load generation. This is not as dire as critics would have us believe, as wind power does not have the market penetration to create a need for major standby capacity (which is already in place in case of outages at a large conventional power plant). as renewable energy takes more market share, however, smart energy storage solutions will be required to ensure system reliability. These include the much-talked-of smart grid, or the promising emerging technology of interseasonal heat transfer (storing heat captured during the summer months for use in the winter).  This is where biopower - burning energy crops, forestry residues or municipal waste - has an advantage. It provides base-load capability and can be implemented quickly and inexpensively compared with large scale wind and solar power (it already accounts for more power generation than wind and solar combined on a global basis.) There are downsides, however, not least public concern about competition between food crops and energy crops.  "The challenge is to use the feedstock in a sustainable manner which gains public support," says Margaret Garn, editor of BioEnergy Insight magazine, which covers this fast-growing sector. "Bioenergy uses an abundant, often waste feedstock, can provide energy independence and reduce greenhouse gas emissions, and above all has the potential to be cost-competitive with traditional forms of energy."  Marine energy also looks very promising given the vast natural resource of this island nation. Scotland's