Environmental Engineering Reference
In-Depth Information
Renewables
On the rise, but an uphill struggle
Renewable energies are the most essential part of the low-carbon
economy. Although investment in renewables took a big hit in the
2008-09 economic recession, their share of the world's energy mix
is rising. Increasing their use, however, remains an uphill struggle,
because in almost every case renewables require government sup-
port or subsidy to compete with fossil fuels. But what are renewable
energies? And why are they harder to generate, both technically and
commercially, than fossil fuels?
The basics
By definition, renewable forms of energy renew or replenish themselves
naturally. Unlike oil, gas, coal or uranium ore for nuclear power - the
reserves of which have not increased since their creation in distant geo-
logical time - we can keep using and re-using solar, wind and tidal power,
and growing crops for biomass (with the proviso of access to adequate
water). There is no finite stock of these renewable energy sources.
Moreover, using them over and over again is sustainable.
These renewable energy sources are clean. They produce none of the
by-products of fossil fuels or nuclear power, such as carbon emissions or
nuclear waste, which damage the climate and make life harder for future
generations. Renewables and the low-carbon economy are key to achiev-
ing the wider goal of energy sustainability. But for an energy system to be
sustainable, supply and demand have to be in balance - and this requires
not only a cleaner supply of energy, but also greater efficiency on the
demand side in using energy.
Before examining each renewable in detail, it is useful to point out one
broad distinction that policy makers increasingly make.
