Biogas - part of the future energy grid

IN 2020, THE ENERGY GRID WILL FEATURE A NEW

source: biogas, generated from domestic

organic waste, using micro anaerobic digesters

(AD). This will enable us to recapture the fuel

value of waste to power our homes and o ces.

Heat and energy microgrids already exist,

including one in Brooklyn, New York, which

makes it possible to exchange locally generated

renewable electricity. This energy is currently

mostly from solar, but it can easily be extended

to include other renewable sources. Indeed,

London’s energy network already integrates

centralised anaerobic digesters.

This type of distributed infrastructure will

initially arrive in cities such as New York, Paris,

Lisbon and Barcelona, which already have local

initiatives in place, and they will be designed

into the fabric of new-build developments in

rapidly urbanising areas. And, as waste-management

units can be incorporated into buildings,

cities will not have to completely overhaul

their ageing infrastructure to accommodate

growing populations and energy demands.

ADs also produce water, and this could be

used in urban farming, air conditioning,

cleaning and general irrigation as well as

helping cities that are facing water shortages

and groundwater depletion. Chennai, Cape

Town, Cairo and Mexico City are already struggling

with these problems, and in 2020, the

numbers will increase. That will also benefit

a city’s energy usage. Transporting water is

energy-costly – in southern California, water

is transported 600km to where it is needed,

on a route that includes a 600-metre-high pass

over the Tehachapi mountains.

To enable more AD units in cities, we must

take steps to address the gap between building

design, legislation and city infrastructure

requirements. But there will be plenty of

non-energy-related reasons to do so, too. On-site

waste-to-energy solutions will reduce the

number of refuse lorries on the road, combating

congestion and the seven million deaths that,

according to the World Health Organisation,

occur annually due to air pollution

Biogas from waste is a hugely under-tapped

resource. In 2020, ADs will enable buildings

to incorporate waste recycling, gas generation

and water-recapture capacities in their core

design, taking us further along the road

to cities being smart and energy e cient.