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Sunday, August 21, 2011

Low Carbon Island 1ton CO2/capita/yr challenge-Cayman Islands

Cayman Islands import nearly all of oil and electricity from neighboring countries. Tourism accounts the larger share of the service sectors followed by insurance, banks and mutual funds. It has been identified that electricity generation and transportation consume major share of oil usage in the country recently. Renewable energy solutions including solar thermal, PV, wind, biofeuls development has been studied to determine their energy and CO2 emission reduction potential. Models of energy systems and their optimization have been carried out using HOMER and the total investment required and the feasibility has also been dealt with.


Energy scenarios

To determine the energy demand by 2030 and thereby estimate the CO2 emission per capita alternative energy scenarios can be developed; the business as usual (BAU) scenario and a sustainable energy scenario.

Business as usual scenario

In this scenario fossil fuels constitute a major portion of primary energy supply. The oil consumption will increase by a minimum of an average increment of the last 5 years. Utilization of renewable energy sources as well as implementation of energy efficiency and conservation is given less concern.

Sustainable energy scenario

In this scenario a combination of renewable energy sources are used to reduce the oil consumption and CO2 emissions. It is assumed a 50% penetration of renewable like biomass, solar and wind by 2030.The base year 2002 is taken as a year where there is negligible contribution of renewable energy sources in primary energy supply in the Islands.

Energy Solution

Alternative energy solutions for Cayman Islands include wind power, solar PV, solar thermal, bio fuels, end use energy efficiency improvements and energy conservation.

Wind power

A wind turbine 1.5MW and the capacity factor of 35% can be considered.

Solar potential

A scenario where a number of solar cells of 1.5m2 area each installed by 2030 can be studied. Assuming 15% efficiency, the energy produced is can be equated with equivalent fossil fuel and hence CO2 reduction.

Solar thermal

Solar water heating is one typical application of solar energy. Flat plate collectors are used to supply water for residential areas and hotels. Solar thermal can be applied in residential area, hotels and villas in Cayman Islands to reduce the energy demand and CO2 emissions.

Residential area model

Residential area hot water demand can be estimated from reference studies. In Japan for instance a family uses 444.9lit/day [24] In UK the average hot water consumption is 50lit/person/day. The average hot water consumption per occupant in houses and hotels can be taken as 90-160lit/day.

Hotel area models

In this model hotels and villas are modeled to determine the hot water demand.

Bio fuels

Bio gas can be used to replace cooking fuels used in hotels and villas.


Energy efficiency

Energy efficiency is focused in three sectors, building (both residential and commercial), manufacturing industries and transportation (primarily automotive).It leads to management of the energy demand in future times and hence controlling the CO2 emissions. In Cayman Islands the financial sector dominated the industry. Energy efficiency in building sector is analyzed in the next sections.


Building

Combined heating and cooling consume the most energy in buildings. Water heating and refrigeration consume most of the energy in residential areas. Electric bulbs and computers also consume more in the commercial building sector. In these buildings amenities like air conditioning, blenders, ceiling fans, coffee makers, cribs, dishwashers, hair dryers, Irons, Jacuzzi, microwaves, oven, refrigerators, and toasters, TV, Washer/Dryer and VCRs are found. Hence there is a huge potential for energy saving if efficiency measures are applied in these sectors.


Commercial building sector

Commercial buildings considered are banks, insurance and mutual fund buildings among others. Hotels, villas and condos are considered separately. Heating and cooling load reduction and efficient electric bulbs are considered as potential energy saving approaches. Heating and cooling load reduction involves energy efficiency improvement on HVAC, energy efficient heating and cooling systems in existing buildings and passive solar design in new buildings.


Heating and cooling loads

Simple models of a typical working area in the financial sector can be used to estimate the heating or cooling demand in the finance sector. The heating or cooling demand is obtained roughly by multiplying the number of offices for banks, insurances and mutual funds by the demand for this typical model.


Here is the summary of results. Find the full document here.


Energy solution

Energy saving potential

CO2 tons/ capita/yr reduction (2030)

Investment required

Energy efficient HVAC in commercial bldg.

26,400MWh/yr

0.16

Minimum, energy saving tips are used

Energy efficient freezer and refrigerator

5800MWh/yr

0.025

Replace 15,462 refrigerators and 3176 freezers by energy start ones.

Efficient light bulbs

4650MWh/yr

0.016

100,000 incandescent bulbs

biogas

638GWh/yr

2.1

5000 digesters of 14cu.m/day biogas production

Solar water heaters

home

hotels

5.31MWh/yr

109Gwh/yr

Total

0.54

a) 33,340 solar panels of 1.5m2 area

b)71,600 solar panels of each 1.5m2 area

Biodiesel

756GWh/yr

2.54

Ten biodiesel plants of 22.2ton/day capacity

Total

1540GWH/yr

5.4



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