sea water air conditioning technical overview

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SWAC TECHNICAL OVERVIEWTechnical Principles of SWAC | Energy Saving Potential | Market Potential

Remi Blokker, CEO Bluerise, Delft, NetherlandsDiego Acevedo, VP BusDev Bluerise, Aruba

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Agenda

Introduction – Diego Acevedo

Technical Principles of SWAC – Remi Blokker

Energy Saving Potential – Diego Acevedo

Market Potential – Remi Blokker

Q & A

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Oceans: largest solar collector and energy storage

Ocean Thermal Energy: highest potential when comparing all ocean energy technologies

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Technical principles of SWACWater is pumped up through a large diameter pipe from the deep ocean to a cooling station

Heat (cold actually) is transferred in the cooling station to a distribution network consisting of insulated pipes

Each customer is connected to the network

A customer substation is used to transfer the cold to the customer’s site


Cold water pipePipeline is made of high density poly-ethylene (HDPE)

Pipe will be towed to holding area from manufacturing location

Pipe will be assembled at holding area and towed to site

Pipeline will be lowered to seafloor, typically using a so-called S-lay

Pipeline will be subsurface along the shoreline (trenched or tunneled)

Pipeline has a lifetime of +30 years


Pump station

Shore landing can be dredged, drilled or tunneled.

Either a dry or wet pit/reservoir can be used, requiring either submerged pumps or a subsurface pump station inside a compact concrete pit

Seawater pumps are used in a redundant manner and require little energy. Optionally, this energy could be supplied by an OTEC generator in tandem with the SWAC


Cooling station

The cooling station is equipped with a series of heat exchangers, which are used to chill a fresh water loop. Salt water is never in contact with customer installations.

Cooling station should be situated at a height close to sealevel, to minimize pumping power

Cooling station will house backup chillers to ensure peak capacity and high uptime and provide redundancy


Distribution network

The distribution network consists of a series of feed and return lines, consisting of insulated pipes, in various diameters

It is important to correctly balance the system in terms of efficiency and cost. Using too small diameters will result in higher pumping costs, too large diameter will result in a higher investment

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Curaçao Airport projected SWAC Network


Customer substation

The customer substation, also known as energy transfer station, is where the cooling is supplied to the customer through a heat exchanger

The substation contains all the required control and sensors to ensure correct pressure, temperature and flow speeds of the supply and return system

Metering of the customer’s energy usage is also performed in the substation

The substation saves space and frees the customer of maintenance

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Automation

The cooling plant, pump station and distribution system are typically controlled by a SCADA system

Plant can be operated remotely. Most functions of e.g. the Amsterdam district cooling networks can be accessed by operator using smartphone

Integrated metering and billing

Sub-metering of individual users possible

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Energy usage of air-conditioning

The energy usage of a chiller/cooling system is expressed as COP, Coefficient of Performance. COP indicates the amount of units of cooling one unit of electricity can provide.

Typical compressor based chillers in the Caribbean obtain COPs of between 3 and 4

The warm, humid air limits these chillers to obtain higher efficiency, e.g. evaporative cooling does not add much to the efficiency because of the high dew point temperature

Cooling to relatively warm water, e.g. surface seawater or a well, can increase COP to a little over 4

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Energy usage of SWAC

The energy usage of SWAC is primarily going to at one side the seawater pumps to transport the deep seawater and on the other side to the distribution pumps to distribute the cold fresh water to the customers

Depending on the temperature of the deep seawater and also on the capacity of the deep seawater pipe, some additional cooling might be required using confentional chillers, also requiring energy

The COP of a well performing SWAC system can easily achieve above 30, meaning that 10 times more cooling is provided per energy unit than for a chiller with a COP of 3. This is why SWAC can save up to 90% of the energy required.

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Cost reduction potential

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Electricity Rate - Jamaica (USD/kwh)

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LCOC =

CAPEX +OPEX t

(1+WACC)tt=1

n

å

Cooling_delivered t

(1+WACC)tt=1

n

å

Cost of cooling is based on the balance between system dimension (driving CAPEX) and current and future demand

Design for expansion -> potential for decrease in cooling cost in time

Simplified levelized cost of cooling formula:

Cost of Cooling

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Cost of Cooling comparison

Medium-sized project

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CO2 Savings Potential

Source Estimated GHG Emissions

Diesel - HFO ~0.6 kg-CO2 /kwh

Coal ~0.8 kg-CO2 /kwh

Example a district cooling system of approximately 12,000 peak tons of A/C capacity on an island with Diesel or HFO based power grid would save over 100,000 tons of CO2 emissions per year

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Key benefitsCustomer Benefits

Energy reduction – 80-90% savings on cooling power Reduced cooling costsElimination of price volatility – long term contractsEnvironmentally benignLess maintenancePlug-and-playLower costs

District BenefitsEnabler for growth and overall economic developmentLower costs of cooling can attract other industries/activitiesReduce A/C peaks for utility

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Market Potential

Energy for Heating –stabilizing• Energy savings – insulation• Climate Change

Energy for Cooling – growing• Increasing prosperity• Climate Change

M. Isaac and D. P. van Vuuren, 2009

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Context - Caribbean

“This region has some of the highest energy costs in the world.

Caribbean countries are particularly vulnerable to the effects of climate change and we have to act now.”,

US President Obama, CARICOM summit, April 2015

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Almost all Caribbean countries have good access for SWAC & OTEC

*NB, eastern side shown, western side also has good access

Context - Caribbean


Techno-economic Potential

Online OTEC resource assessment tool:

my.oceanpotential.com

Global datasets provide great insights in the potentially available resource for any given location

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Fossil fuels • Most Caribbean countries do not have fossil resources and need to import• Serious energy security risks • LNG & CNG do not change this• Fossil fuels emit large amounts of greenhouse gas• Low-carbon fossil a false hope?

Nuclear – not sustainable, and requires scale that is probably prohibitive for Caribbean

Renewables – only real option for sustainable, energy-secure, future• Hydro – mature, very dependent on local conditions• Wind – mature, intermittent• Solar – mature, intermittent• SWAC, mature, baseload• OTEC, near-commercial, baseload• Geothermal – semi-mature, baseload, very dependent on local conditions, considerable risk with drilling• Biomass – mature, but arguably non-sustainable, large land usage, competing with food

Renewable Energy Options in Caribbean


Island renewable energy mix exampleAruba case

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Island renewable energy mix exampleEnergy mix with intermittent renewables

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one week

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Island renewable energy mix exampleEnergy mix with intermittent and baseload renewables


Techno-economic Feasibility

Rough Indicators:

Deep sea within ~10km from coastline

The closer the better

Concentrated cooling loads within 10km from coast > 3000 tons of A/C

The larger the better

Ideally large buildings with centralized A/C units (e.g. Chillers)

Potential customers:

Hotels + Resorts, Airports, Data Centers, Commercial centers, Big Box stores, Housing complexes, Industry

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Project Enablers

Parallels to Solar/Wind energy financing, with the difference of having a multitude of customers, instead of one PPA contract

Infrastructure utility type of investment = Need for long term contracts

Take or pay contracts possible, need for credit worthy local entity

BOOT concessionary contracting, shift development and construction risk to private sector while optimizing long term energy pricing

Systems can be dimensioned to current need but more cost efficient to size for future demand. Demand growth risk

Innovation can benefit from grants for EIA, capacity development, de-risking in terms of site, permitting, regulatory framework, lower cost of capital translating into lower cost of cooling to the end-users.

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Other Market Opportunities

Virtually free of pathogen deep seawater is ideal for keeping brood-stock and the growing of high value fish.

Seawater cooled greenhouses allow to grow crops that normally only grow in more temperate climates

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Other Market Opportunities

The cold water found in the deep ocean is a key enabler for a broad range of sustainable applications.